Intraocular lens adapted for accommodation via electrical signals

ABSTRACT

A lens system is provided. The lens system can include a lens adapted to be part of the optical pathway of an eye and a sensor. The sensor is adapted to sense a condition. The lens system also includes a control unit. The control unit is adapted to receive a signal from the sensor. The signal includes information about the condition. The control unit is operable to alter the shape of the lens based at least partly upon the condition. The lens can be adapted for positioning inside the capsular bag of the eye, in the posterior chamber of the eye, in place of the capsular bag of the eye or in the cornea. The sensor can be a tension sensor. The condition can be the amount of tension at the zonules of the eye. The control system can include a fluidic pressure generator and a fluid flow control device.

BACKGROUND

An eye can have various disorders which affect the crystalline lens ofthe eye. One of the most common disorders is cataracts, which is aclouding of the crystalline lens. The conventional treatment forcataracts is removal of the crystalline lens and replacement of the lenswith an artificial or intraocular lens (IOL).

Once an IOL is implanted, however, it generally has a fixed refractivepower. This presents a problem with respect to both far and near vision.With respect to far vision, the diopter power of the IOL is generallynot capable of perfect vision—i.e. 20/20. This problem is due to thefact that the refractive power of the IOL must be chosen prior toimplantation and thus can only be approximated. Since the diopter powercan only be approximated, most patients will require at least a ±1.00diopter power correction along the optical path to provide perfectvision. With respect to near vision, an artificial lens results in aloss of accommodation (i.e., the process of focusing the eye between farobjects and near objects).

SUMMARY

In one embodiment, a lens system is provided. The lens system includes alens adapted to be part of the optical pathway of an eye and a sensor.The sensor is adapted to sense a condition. The lens system alsoincludes a control unit. The control unit is adapted to receive a signalfrom the sensor. The signal includes information about the condition.The control unit is also operable with the lens to alter the shape ofthe lens based at least partly upon the condition.

The lens can be adapted for positioning inside the capsular bag of theeye, in the posterior chamber of the eye, in place of the capsular bagof the eye or in the cornea. The sensor can be a tension sensor. Thecondition can be the amount of tension at the zonules of the eye. Thecontrol system can be operable with the lens to alter the shape of thelens by passing a current through the lens. The control system caninclude a fluidic pressure generator and a fluid flow control device.The lens can include a chamber adapted to receive a fluid. Further, thecontrol system can be operable with the lens to alter the shape of thelens by changing the fluidic pressure in the chamber. The fluid can be asodium chromate solution. The chamber can be at least partly enclosed bya flexible membrane. The sensor can be a wireless signal receiver.

In another embodiment, a lens is provided. The lens includes a flexiblemembrane and a chamber adapted to receive a fluid. The flexible membraneis adapted to at least partly enclose the chamber. The lens is adaptedto be part of the optical pathway of an eye. The chamber is fluidlycoupled to a control unit, and the control unit is operable to controlthe fluidic pressure inside the chamber.

The fluid can be a sodium chromate solution. The control unit canreceive a signal from a sensor, wherein the signal includes informationabout a condition. The sensor can be a tension sensor. The condition canbe the amount of tension at the zonules of the eye. The sensor can be awireless signal receiver.

In another embodiment, a control unit is provided. The control unitincludes a fluidic pressure generator and an electronic circuit. Thecontrol unit is coupled to a lens, and the lens includes a chamberadapted to receive a fluid and a flexible membrane, wherein the flexiblemembrane is adapted to at least partly enclose the chamber. The lens isadapted to be part of the optical pathway of an eye. The chamber isfluidly coupled to the fluidic pressure generator, and the electroniccircuit is operable to control the fluidic pressure generator. Thefluidic pressure generator is operable to change the fluidic pressureinside the chamber.

The fluid can be a sodium chromate solution. The electronic circuit canreceive a signal from a sensor, wherein the signal includes informationabout a condition. The sensor can be a tension sensor. The condition canbe the amount of tension at the zonules of the eye.

Additional features and advantages are described herein, and will beapparent from, the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a side elevational view in section taken through the center ofan eye showing the cornea, pupil, crystalline lens, and capsular bag.

FIG. 2 is a side elevational view in section of the eye shown in FIG. 1showing the capsular bag after removal of the crystalline lens.

FIG. 3 is a side elevational view in section of the eye shown in FIG. 2showing the treatment of the interior of the capsular bag with a liquidto prevent capsular opacification.

FIG. 4 is a side elevational view in section of the eye shown in FIG. 3showing placement of a replacement lens into the capsular bag.

FIG. 5 is a side elevational view in section of the eye shown in FIG. 3in which a replacement lens is positioned in the capsular bag and afluidic system and remote power unit are positioned in the posteriorchamber.

FIG. 6 is a flow chart of the process of accommodation in accordancewith one embodiment of the present invention.

FIG. 7 is a flow chart of the process of accommodation in which thefluidic system includes a pressure sensor for sensing the pressure in atleast one of the chambers in accordance with one embodiment of thepresent invention.

FIG. 8 is a side elevational view in section of the eye shown in FIG. 3in which a replacement lens is positioned in the capsular bag and apower unit is positioned in the posterior chamber.

FIG. 9 is a flow chart of the process of accommodation in response toelectrical signals in accordance with one embodiment of the presentinvention.

DETAILED DESCRIPTION

In various embodiments, a lens capable of accommodation in response toelectrical signals is provided. The lens can be placed at any suitablelocation along the optical path of an eye, including but not limited towithin the capsular bag, in place of the capsular bag, within theposterior chamber or on, in or behind the cornea. Further, it should benoted that any suitable section of the capsular bag can be removed,including but not limited to an anterior portion or a posterior portionaround the main optical axis of the eye. The lens is preferably coupledto a fluidic pumping system which is also coupled to a control systemwhich preferably includes a power source and a signal generation unit.

Referring initially to FIG. 1, a normal eye 10 has a cornea 12, an iris14, and a crystalline lens 16. The crystalline lens 16 is containedwithin a capsular bag 18 that is supported by zonules 20. The zonules20, in turn, are connected to the ciliary muscle 22. According toHelmholz's theory of accommodation, upon contraction of the ciliarymuscle 22, the tension on the zonules 20 is released. The elasticity ofthe lens causes the curvature of the lens 16 to increase, therebyproviding increased refractive power for near vision. Conversely, duringdis-accommodation, the ciliary muscle 22 is relaxed, increasing thetension on the zonules 20 and flattening the lens 16 to provide theproper refractive power for far vision.

If the electrically accommodating lens is to be positioned within thecapsular bag and, thus, replace the crystalline lens, a suitable firststep is to remove the existing lens. As illustrated in FIG. 2, the lensis preferably removed using any technique which allows removal of thelens through a relatively small incision, preferably about a 1-2 mmincision. The preferred method is to create a relatively small incision24 in the cornea 12 and then perform a capsulorhexis to create anopening 26 into the anterior side 28 of the capsular bag 18. Anultrasonic probe 30 is inserted into the capsular bag 18 through theopening 26. The probe's vibrating tip 32 emulsifies the lens 16 intotiny fragments that are suctioned out of the capsular bag by anattachment on the probe tip (not shown). Alternatively, the lensectomymay be performed by laser phacoemulsification or irrigation andaspiration.

Once the crystalline lens 16 has been removed, the capsular bag 18 canbe treated to help prevent a phenomenon known as capsular opacification.Capsular opacification is caused by the proliferated growth of theepithelial cells on the lens capsule. This growth can result in thecells covering all or a substantial portion of the front and rearsurfaces of the lens capsule, which can cause the lens capsule to becomecloudy and thus adversely affect the patient's vision. These cells canbe removed by known techniques, such as by scraping away the epithelialcells; however, it is often difficult to remove all of the unwantedcells. Furthermore, after time, the unwanted cells typically grow back,requiring further surgery. To prevent capsular opacification, thecapsular bag 18 is preferably treated to eliminate the proliferatedgrowth of epithelial cells, as described below.

As seen in FIG. 3, one method of treating the epithelial cells toprevent capsular opacification is to use a cannula 34 to introduce awarm liquid 36 (preferably about <60° C.) into the capsular bag 18,filling the capsular bag 18. The liquid contains a suitable chemicalthat kills the remaining lens cells in the capsular bag and also cleansthe interior of the capsular bag. Suitable chemicals, as well as othersuitable methods of treatment that prevent capsular opacification aredisclosed in U.S. Pat. No. 6,673,067 to Peyman, which is hereinincorporated by reference in its entirety.

As shown in FIG. 4, a replacement lens 38 is then positioned within thecapsular bag 18. Preferably, the lens 38 can be folded or rolled andinserted through the incision in the capsular bag 18; however, the lens38 can be rigid and/or can be inserted through a larger second incisionin the capsular bag 18 or the initial incision, possibly after theinitial incision is widened, or in any other suitable manner. Preferablythe lens 38 varies its focal length in response to changes in fluidicpressure within the lens made in accordance with electrical signals;however the lens 38 can change its index of refraction or alter itsfocal length in any other suitable manner. Since the capsular bag 18 isstill in place, the capsular bag can still assist in accommodation;however, it is not necessary for capsular bag 18 to assist withaccommodation. The lens, as shown in FIG. 5, preferably includes twochambers 40 set on opposite sides of a substrate 42 and covered with aflexible membrane 44; however, the lens can have one or any othersuitable number of chambers. Preferably, the two chambers 40 contain afluid 46, and preferably the fluid 46 is a sodium chromate solution;however, if desired, one or more of the chambers can contain somethingother than a fluid or the chambers can contain different fluids ordifferent sodium chromate solutions. The substrate 42 is preferablyglass; however, the substrate 42 can be any suitable material.Preferably, the flexible membrane 44 is a biocompatible material;however, the flexible membrane can be any suitable material.

Preferably, the fluidic pressure within the chambers 40 can be alteredusing a fluidic system 48 which includes a miniature fluidic pressuregenerator (e.g., a pump or any other suitable device), a fluid flowcontrol device (e.g., a valve or any other suitable device), a controlcircuit and a pressure sensor; however, the fluidic pressure can bealtered in any suitable manner. Further, if desired, a fluidic system 48does not need a pressure sensor. When subjected to electrical signal,the electronic control circuit of the fluidic system 48 controls thevalves and pumps to adjust the fluidic pressure in one or more of thechambers 40. Preferably, the fluidic pressure is adjusted by pumpingfluid in or releasing a valve to allow fluid to flow out and back intothe system 48; however, the fluidic pressure can be adjusted by pumpingfluid out or in any other suitable manner. As a result, the shape andthe focal length of the lens 38 is altered, providing accommodation.Lenses that similarly change focal length in response to fluidicpressure changes made in accordance with electrical signals aredescribed in greater detail in “Integrated Fluidic Adaptive Zoom Lens”,Optics Letters, Vol. 29, Issue 24, 2855-2857, December 2004, the entirecontents of which is hereby incorporated by reference.

As shown in FIG. 5, fluidic system 48 is preferably positioned in theposterior chamber 50; however, the fluidic system 48 can be positionedoutside the eye, within the sclera, between the sclera and the choroidsor any other suitable location. Further, the fluidic system 48 ispreferably positioned such that it is not in the visual pathway. A tube52 fluidly connects the lens 38 and the fluidic system 48. Preferably,the tube 52 passes through a small incision in the capsular bag 18 nearthe connection of the zonules 20 and the capsular bag 18; however, thetube 52 can pass through the capsular bag in any suitable location.

Preferably, fluidic system 48 includes a power source which ispreferably rechargeable through induction or other suitable means suchas generating and storing electrical energy using eye and/or headmovement to provide the energy to drive the generator; however, fluidicsystem 48 can be connected to a remote power source 54 as shown in FIG.5 or to any other suitable power source. Preferably, the remote powersource 54 is located in the posterior chamber 50; however, the remotepower source 54 can be positioned outside the eye (e.g., under thescalp, within a sinus cavity, under the cheek, in the torso or in anyother suitable location), within the sclera, between the sclera and thechoroids or any other suitable location. Further, the remote powersource 54 is preferably positioned such that it is not in the visualpathway. The remote power source 54 is preferably electrically coupledto the fluidic system 48 by electrically conductive line 56; however,the remote power source 54 can be coupled to the fluidic system 48 inany suitable manner. Further, the remote power source 54 preferablyincludes a signal generator which can supply control signals to thefluidic system 48 via electrically conductive line 56; however, theremote power source 54 can be without a signal generator, if desired, orcan supply control signals to the fluidic system 48 in any suitablemanner. Similar remote power sources are described in more detail inU.S. Pat. No. 6,947,782 to Schulman et al., which is herein incorporatedby reference in its entirety.

Preferably, the remote power source 54 is coupled to a sensor 58 byelectrically conductive line 60; however, the remote power source 54 canbe coupled to sensor 58 in any suitable manner. The sensor 58 ispreferably a tension sensor positioned on the zonules 20 so that thesensor 58 detects the amount of tension present in the zonules 20;however, the sensor 58 can be a wireless signal sensor, aneurotransmitter sensor, a chemical sensor, a pressure sensor or anyother suitable sensor type and/or can be positioned in or near theciliary muscle 22, at or near the nerve controlling the ciliary muscle22, in the capsular bag 18 or in any other suitable location.Preferably, the sensor 58 detects the eye's attempt to cause its lens toaccommodate; however, the sensor 58 can detect a manual attempt toaccommodate the lens 38 (e.g., input through a wireless controller) orany other suitable input. The information detected at the sensor 58 isrelayed to the remote power source 54 via line 60, and the signalgenerator of the remote power source 54 generates a signal in accordancewith the information. The signal is sent to the fluidic system 48, whichadjusts the fluidic pressure in one or more of the chambers 40accordingly. Thus, the eye's natural attempts to focus will result inaccommodation of lens 38. Response of lens 38 may vary from that of thenatural lens; however, the neural systems which control the ciliarymuscle 22 (and therefore the tension on the zonules 20), are providedwith feedback from the optic nerve and visual neural pathways. As aresult, the neural system can learn and adjust to the characteristics ofthe lens 38.

The process of accommodation in accordance with one embodiment is shownin FIG. 6. At step 600, the eye attempts to refocus at a differentdistance, and thus changes the tension on the zonules. At step 610, atension sensor detects the new tension level and relays the informationto a control unit. The control unit preferably includes a remote powersource and a fluidic system; however, the control unit can include anysuitable devices. At step 620, the control unit determines the correctadjustment to be made to the fluidic pressure in at least one chamber ofa fluidic lens in response to the tension sensor information. At step630, the control unit makes the determined fluidic pressure adjustmentand the process repeats at step 600.

Another process of accommodation in accordance with another embodimentin which the fluidic system includes a pressure sensor for sensing thepressure in at least one of the chambers is shown in FIG. 7. At step700, a user sends a signal to refocus his or her eye at a differentdistance. Preferably, the signal is sent wirelessly; however, the signalcan be sent in any suitable manner. Further, the signal preferablyincludes information corresponding to the desired different distance;however, the signal can include information indicating only that thedesired distance is closer or farther or any other suitable information.At step 710, a sensor detects the signal and relays the information to acontrol unit. The control unit preferably includes a remote power sourceand a fluidic system; however, the control unit can include any suitabledevices. At step 720, the control unit determines a new fluidic pressurelevel to be created in at least one chamber of a fluidic lens inresponse to the sensor information. At step 730, the control unitincreases or decreases, as appropriate given the current fluidicpressure as determined by the pressure sensor, the fluidic pressure inthe chamber. At step 740 it is determined whether the desired fluidicpressure is equal to the pressure sensed by the pressure sensor. If thedesired fluidic pressure is equal to the pressure sensed by the pressuresensor, at step 750, the lens is accommodated and the process repeats atstep 700. If the desired fluidic pressure is not equal to the pressuresensed by the pressure sensor, the process repeats at step 730.

FIG. 8 illustrates an alternative accommodating lens 62. Lens 62responds to electrical stimulation by changing its focal length. Similarto lens 38, lens 62 is preferably placed within the capsular bag 18;however, the lens 62 can be placed in the posterior chamber 50, in placeof the capsular bag 18, within the cornea 12, on the surface of the eyeor in any other suitable location. Further, it should be noted that anysuitable section of the capsular bag can be removed, including but notlimited to an anterior portion or a posterior portion around the mainoptical axis of the eye. If the lens 62 is placed within the capsularbag 18, the capsular bag can assist with accommodation; however, it isnot necessary for the capsular bag 18 to assist with accommodation. Lens62 may have one or more chambers that are at least partly filled with afluid or other substance; however, lens 62 is not required to have achamber.

Preferably, lens 62 is a fluid lens that alters its focal length bychanging its shape; however lens 62 can be any suitable type of lens andcan change its focal length in any suitable manner. The lens 62preferably includes two immiscible (i.e., non-mixing) fluids ofdifferent refractive index (or other suitable optical property);however, the lens 62 is not required to include two immiscible fluids ofdifferent refractive index. Preferably, one of the immiscible fluids isan electrically conducting aqueous solution and the other anelectrically non-conducting oil, contained in a short tube withtransparent end caps; however, the immiscible fluids can be any suitablefluids and can be contained in any suitable container. The internalsurfaces of the tube wall and one of its end caps are preferably coatedwith a hydrophobic coating that causes the aqueous solution to formitself into a hemispherical mass at the opposite end of the tube, whereit acts as a spherically curved lens; however, the hydrophobic coatingis not required and, if present, can be arranged in any suitable manner.Further, the coating can include any suitable material, includinghydrophilic substances.

Preferably, the shape of the lens 62 can be adjusted by applying anelectric field across the hydrophobic coating such that it becomes lesshydrophobic (a process called “electrowetting” that results from anelectrically induced change in surface-tension); however, the shape ofthe lens 62 can be adjusted by applying an electric field across anysuitable portion of the lens 62. Preferably, as a result of this changein surface-tension, the aqueous solution begins to wet the sidewalls ofthe tube, altering the radius of curvature of the meniscus between thetwo fluids and hence the focal length of the lens. Increasing theapplied electric field can preferably cause the surface of the initiallyconvex lens to become less convex, substantially flat or concave;however increasing the applied electric field can cause the surface ofthe lens to change in any suitable manner. Preferably, decreasing theapplied electric field has the opposite effect, enabling the lens 62 totransition smoothly from being convergent to divergent, or vice versa,and back again repeatably.

The lens 62 can measure 3 mm in diameter by 2.2 mm in length; howeverthe lens 62 can have any suitable dimensions. The focal range of thelens 62 can be any suitable range and can extend to infinity. Further,switching over the full focal range can occur in less than 10 ms or anyother suitable amount of time. Preferably, lens 62 is controlled by a DCvoltage and presents a capacitive load; however, the lens 62 can becontrolled by any suitable voltage and operate with any suitableelectrical properties.

Lens 62 is electrically coupled to a power source 64 by electricallyconductive line 66; however, lens 62 can be coupled to power source 64in any suitable manner. Preferably, power source 64 is rechargeablethrough induction or other suitable means such as generating and storingelectrical energy using eye and/or head movement to provide the energyto drive the generator; however, the power source 64 can benon-rechargeable, if desired. Similar to remote power source 54, thepower source 64 is preferably located in the posterior chamber 50;however, the power source 64 can be positioned outside the eye (e.g.,under the scalp, within a sinus cavity, under the cheek, in the torso orin any other suitable location), within the sclera, between the scleraand the choroids or any other suitable location. Further, the powersource 64 is preferably positioned such that it is not in the visualpathway. The power source 64 preferably includes a signal generatorwhich can supply current to the lens 62 via electrically conductive line66; however, the power source 64 can be without a signal generator, ifdesired, or can supply control signals to the lens 62 in any suitablemanner.

Preferably, the power source 64 is coupled to a sensor 68 byelectrically conductive line 70; however, the power source 64 can becoupled to sensor 68 in any suitable manner. The sensor 68 is preferablya tension sensor positioned on the zonules 20 so that the sensor 68detects the amount of tension present in the zonules 20; however, thesensor 68 can be a wireless signal sensor, a neurotransmitter sensor, achemical sensor, a pressure sensor or any other suitable sensor typeand/or can be positioned in or near the ciliary muscle 22, at or nearthe nerve controlling the ciliary muscle 22, in the capsular bag 18 orin any other suitable location. Preferably, the sensor 68 detects theeye's attempt to cause its lens to accommodate; however, the sensor 68can detect a manual attempt to accommodate the lens 62 (e.g., inputthrough a wireless controller) or any other suitable input. Theinformation detected at the sensor 68 is relayed to the power source 64via line 70, and the signal generator of the power source 64 generates asignal in accordance with the information. The signal is sent and passedthrough the lens 62, which preferably changes shape as a result of theelectrical current flowing through it; however, the lens 62 could changeits index of refraction in response to the electrical current flowingthrough it or change its focal length in any other suitable manner.Preferably, line 70 includes two separate electrical pathways thatelectrically couple to lens 62 at different, preferably substantiallyopposite, locations so that one of the pathways can serve as a groundwire; however, the lens 62 can be grounded in any other suitable mannerto enable current supplied via line 70 to flow through the lens 62. As aresult, similar to lens 38, the eye's natural attempts to focus willresult in accommodation of lens 62. Response of lens 62 may vary fromthat of the natural lens; however, as with lens 38, the neural systemswhich control the ciliary muscle 22 (and therefore the tension on thezonules 20), are provided with feedback from the optic nerve and visualneural pathways. As a result, the neural system can learn and adjust tothe characteristics of the lens 62.

The process of accommodation in response to electrical signals inaccordance with one embodiment is shown in FIG. 9. At step 900, the eyeattempts to refocus at a different distance, and thus changes thetension on the zonules. At step 910, a tension sensor detects the newtension level and relays the information to a control unit. The controlunit preferably includes a power source; however, the control unit caninclude any suitable devices. At step 920, the control unit determinesthe correct adjustment to be made to the current being passed throughthe lens in response to the tension sensor information. At step 930, thecontrol unit adjusts the current being passed through the lens and theprocess repeats at step 900.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

1. A lens system comprising: a lens positioned within an eye; and acontrol unit, wherein said control unit is operable with said lens toalter the focal length of said lens based at least partly upon acondition.
 2. The lens system of claim 1, wherein said lens is adaptedfor positioning at a location selected from the group consisting ofinside the substantially capsular bag of the eye, inside the capsularbag of the eye in which an anterior portion of the capsular bag aroundthe optical axis of the eye is removed, inside the capsular bag of theeye in which a posterior portion of the capsular bag around the opticalaxis of the eye is removed, the posterior chamber of the eye, theanterior chamber of the eye, in place of the capsular bag of the eye,and the cornea.
 3. The lens system of claim 1, further comprising: asensor, wherein said sensor is adapted to sense the condition andwherein said control unit is adapted to receive a signal from saidsensor, wherein the signal includes information about the condition. 4.The lens system of claim 3, wherein said condition is the amount oftension at the zonules of the eye.
 5. The lens system of claim 1,wherein said control system is operable with said lens to alter thefocal length of said lens by passing a current through said lens.
 6. Thelens system of claim 1, wherein said control system includes a fluidicpressure generator and a fluid flow control device, wherein said lensincludes a chamber adapted to receive a fluid, and wherein said controlsystem is operable with said lens to alter the focal length of said lensby changing the fluidic pressure in the chamber.
 7. The lens system ofclaim 6, wherein the chamber is at least partly enclosed by a flexiblemembrane.
 8. A lens comprising: a chamber adapted to house a substance,said lens being adapted to be positioned in an eye, wherein said lens iscoupled to a control unit, wherein the control unit is operable tocontrol the focal length of said lens by influencing the substance. 9.The lens of claim 8, wherein influencing the substance includes applyingan electrical field across the substance.
 10. The lens of claim 8,wherein influencing the substance includes changing the pressure of thesubstance in the chamber.
 11. The lens of claim 8, wherein the controlunit receives a signal from a sensor, wherein the signal includesinformation about a condition.
 12. The lens of claim 11, wherein thecondition is the amount of tension at the zonules of the eye.
 13. Acontrol unit comprising: an electronic circuit; wherein said controlunit is coupled to a lens, said lens including a chamber, which isadapted to house a substance, said lens being adapted to be positionedin an eye, said electronic circuit being operable to control the focallength of the lens.
 14. The control unit of claim 13, wherein saidelectronic circuit being operable to control the focal length of thelens by applying an electric field to the substance.
 15. The controlunit of claim 13, wherein said electronic circuit receives a signal froma sensor, wherein the signal includes information about a condition. 16.The control unit of claim 15, wherein the condition is the amount oftension at the zonules of the eye.
 17. An intraocular lens, comprising:a lens body; and a control system adapted to alter the refractiveproperties of the lens body such that the lens body at least partlyassists in accommodation.
 18. The intraocular lens of claim 17, whereinthe control system is adapted to alter the refractive properties of thelens body by altering the shape of the lens body.
 19. The intraocularlens of claim 17, wherein the control system is adapted to alter theshape of the lens body by altering the fluidic pressure in at least onechamber in the lens body.
 20. The intraocular lens of claim 17, whereinthe control system is adapted to alter the refractive properties of thelens body by altering the refractive index of at least one portion ofthe lens body.
 21. A lens system comprising: a lens positioned along theoptical path of an eye; and a control unit, wherein said control unit isoperable with said lens to alter the focal length of said lens based atleast partly upon a condition.
 22. The lens of claim 21, wherein saidlens is positioned within the eye.
 23. The lens of claim 21, wherein thecontrol unit is operable to alter the focal length of said lens inresponse to a manual input.
 24. The lens of claim 21, wherein thecontrol unit is operable to automatically alter the focal length of saidlens.